(1) Field of the Invention
The present invention generally relates to a disk drive for use in a computer system, and more particularly to a disk drive having a disk loading mechanism in which a disk from a disk holder unit is transported to a playback position and the disk at the playback position is clamped by a clamper on a turntable when a data signal is reproduced from the disk.
(2) Description of the Related Art
A CD-ROM disk drive for use in a computer system is known. In the CD-ROM disk drive, a CD-ROM (Compact Disk--Read Only Memory) from a disk holder unit is transported to a playback position and the CD-ROM at the playback position is clamped by a clamper on a turntable. The CD-ROM clamped by the clamper is rotated by the turntable when a data signal is reproduced from the CD-ROM.
It is desirable that the CD-ROM which is processed by the CD-ROM disk drive to reproduce the data signal is hardly deformed when the CD-ROM above the turntable is clamped by the clamper or when the CD-ROM clamped on the turntable is released by the clamper.
The CD-ROM is a type of data recording medium. Hereinafter, the CD-ROM will be called the disk for the sake of convenience.
FIGS. 1A through 1D show a conventional disk clamping mechanism 300 used for a disk drive.
As shown in FIGS. 1A and 1B, in the conventional disk clamping mechanism 300, a disk 11 is placed between a turntable 301 and a clamper 303. The disk 11 when it is supported on the turntable 301 is rotated by the turntable 301 around the center of the turntable 301. A clamper holder 302 movably supports the clamper 303, and moves up and down the clamper 303 according to a movement of the clamper holder 302.
In the above disk clamping mechanism 300, the peripheral edge 11a of the disk 11 is held by a pair of holding members 304 and 305 when the disk 11 above the turntable 301 is clamped by the clamper 303 or when the disk 11 clamped on the turntable 301 is released by the clamper 303.
As shown in FIGS. 1A and 1B, when the disk 11 above the turntable 301 is clamped by the clamper 303, the turntable 301 is moved up toward the clamper 303 and the clamper holder 302 is maintained at an upper position "H100". If the disk 11 deviates from the center of the turntable 301, the clamping of the disk 11 between the turntable 301 and the clamper 303 may be defective and a deformation of the disk 11 on the turntable 301 may occur when the turntable 301 is moved up, as shown in FIG. 1B. Since the clamper holder 302 is maintained at the upper position "H100", the clamper 303 is retained by the clamper holder 302 at the upper position "H100". When the turntable 301 is moved up, the clamping of the disk 11 between the turntable 301 and the clamper 303 may be incomplete. Therefore, the disk 11 when it is clamped on the turntable 301 is deformed.
As shown in FIGS. 1C and 1D, when the disk 11 clamped on the turntable 301 is released by the clamper 303, the turntable 301 is moved down away from the clamper 303 and the clamper holder 302 is maintained at a lower position "H101". Since the clamper holder 302 is maintained at the lower position "H101", the clamper holder 302 can be moved up from the lower position "H101" by a difference "j" in the height between the upper position "H100" and the lower position "H101". Therefore, with respect to the clamper holder 302, the clamper 303 can be moved down from the position shown by FIG. 1C by the difference "j". The clamper 303 is attracted by the turntable 301 by using an electromagnetic force when the disk 11 is placed between the turntable 301 and the clamper 303. Therefore, when the turntable 301 is moved down, the clamper 303 is moved down together with the turntable 301. The releasing of the disk 11 on the turntable 301 from the clamper 303 may be incomplete and the disk 11 at this time is deformed as shown in FIG. 1D.
Accordingly, the above-described conventional disk clamping mechanism 300 has a problem in that the disk 11 may be deformed when the disk 11 above the turntable 301 is clamped or when the disk 11 clamped on the turntable 301 is released by the clamper 303. A deformation of the disk is detrimental to data recorded on the disk and a reproducing operation of the disk drive.